Dr. Seamans said this was good because A great deal of work has been done in this field. There is a danger that our people in NASA centers could repeat what has already been done or whatever is already going on in this field. We are relying very heavily on industries and the universities. and so on and so forth. This also applies to the Department of Defense in the department of electronic control. Apparently, there's been a considerable change of opinion in this particular area since last year. Dr. KELLEY. That was approximately 1 year ago. Mr. KARTH. That was March 7, to be exact. Dr. KELLEY. I was directed, in March, to look into the whole situation. That was the status quo at that particular time and, I believe, as a result of our effort, since that time, that we do feel differently. Mr. KARTH. I want to thank you very much, Doctor. I have enjoyed your appearance before the subcommittee and I'm sure the other subcommittee members have, too. On behalf of the subcommittee, I want to congratulate you. You have done a tremendously able job calling to our attention your viewpoint and, apparently, those of NASA, on this particular issue. If we should find reason to call you back later on, we hope we don't interrupt your busy schedule too much. For the benefit of the committee, tomorrow we would meet in this room, at 10:15 and, Mr. Sloop, I would hope that you could be available for the committee at that time. I would also like to announce the subcommittee intends to hold hearings Monday, Tuesday, and Wednesday next week. The place of the hearings has not yet been determined, but we will get that information. Thank you very much. The meeting is adjourned. (Whereupon at 12:10 p.m. the subcommittee was adjourned until 10:15 a.m., Friday, April 5, 1963.) 1964 NASA AUTHORIZATION FRIDAY, APRIL 5, 1963 HOUSE OF REPRESENTATIVES, SUBCOMMITTEE ON SPACE SCIENCES AND ADVANCED RESEARCH AND TECHNOLOGY, Washington, D.C. The subcommittee met, pursuant to adjournment, at 10:15 a.m., in room 304, Old House Office Building, Hon. Joseph E. Karth (chairman of the subcommittee) presiding. Mr. KARTH. The committee will come to order. Dr. Bisplinghoff, I understand that Mr. Sloop has a prepared statement. Dr. BISPLINGHOFF. Yes, sir; he is right here. Mr. KARTH. You may proceed, Mr. Sloop. Perhaps it would be best if you don't follow the prepared statement verbatim, but summarize it, using whatever slides or other material you have. STATEMENT OF JOHN L. SLOOP, DIRECTOR, PROPULSION AND POWER GENERATION, OFFICE OF ADVANCED RESEARCH AND TECHNOLOGY, NASA INTRODUCTION Mr. Chairman and members of the subcommittee, Dr. Bisplinghoff has outlined to you our concept of advanced research and technology and described various programs. I shall amplify his remarks with regard to two of these programs: Chemical propulsion and space power. These programs are closely related as they both are energy conversion processes. The energy sources to be considered here are chemical and solar; nuclear energy is handled separately by Mr. Finger. Propulsion is the key to space exploration and our push to the Moon in this decade will depend completely on chemical propulsion. We see a large and continuing role for chemical propulsion in the next decade. The advent of nuclear and electrical propulsion will greatly increase our capability and enable us to use each type in the application best suited to its characteristics. We see much larger chemical propulsion systems than we have today. Some of these may use air augmentation and will be capable of ferrying large payloads economically from Earth to manned satellites and between distant points on the Earth. We see chemical propulsion packages carried dormant for months on long space missions but ready at the touch of a button or a signal from Earth to perform their task. We see chemical propulsion systems for landing and takeoff from the Moon, Mars, and Venus where compact systems of high thrust per pound of weight are needed. Some may be carried as extra stored energy sources for emergency use. Space power or electric power generation is the heart of a spacecraft, supplying its many parts with electrical power. It provides power for communications, guidance control, measurements, mechanical devices, life support, and in special cases, for propulsion. Present spacecraft use solar cell and battery power systems but the technology is developing so rapidly there will soon be many other systems available, each of which has its special application. We visualize large areas of inflatable structures covered with solar cells and connected with regenerative fuel cells for continuous power in and out of sunlight periods. We see an increasing use of regenerative or rechargeable fuel cells for use in mobile equipment. We see the possibility of large foldable or inflatable solar mirrors to concentrate solar energy into boilers where it is first converted and stored as thermal energy and then converted into electrical energy by thermionic, thermoelectric, magnetohydrodynamic, and conventional heat engines. We see other possibilities for power generation such as biological fuel cells and engines that operate on the fuel and oxidizers carried aboard the spacecraft. Many of these systems will also find useful applications on Earth. It is our job to increase our knowledge about the processes that release chemical and solar energy and how to convert the energy into useful work in propulsion and power generation systems. We do this with advanced research and technology programs involving scientists and engineers in NASA centers, industry, and universities plus nonprofit organizations and other Government agencies. In fiscal year 1963, the division of effort in these three groups is 28, 68, and 4 percent, respectively. In the following discussion, examples of typical work are given and often the organization connected with the particular example is mentioned to give you a sample of the spread of effort. No attempt was made to include all the organizations contributing to the research and technology programs. CHEMICAL PROPULSION Figure 217 (p. 2301) indicates areas of interest in chemical propulsion. Included are engines with liquid and solid propellants and hybrids with a combination of both, rocket engines that use air (or planetary atmosphere) for thrust augmentation, and others that use solar energy. Some of these are pictured; starting at the top left, is a solid motor, a hybrid engine, a radiation cooled thrust chamber, a large booster engine, an engine with air augmentation, and a schematic diagram of a spacecraft engine. We are interested in high-energy propellants for these engines and in better knowledge of combustion phenomena. In fluid dynamics, we wish to learn more about propellant flow in tanks, pumps, lines, coolant passages, and injectors as well as gas dynamics of the combustion gases expanding through the nozzle. We need improved cooling techniques and materials capable of handling gas temperatures from 6,000 to over 10,000° F. For your convenience, these areas will be discussed in the five subdivisions given in the budget book. Analysis, aerothermochemistry, and materials System analyses related to possible future missions are needed on a continuing basis to guide research and technology programs in the most fruitful direction. In considering propulsion requirements for future missions, assessments are made of the state of the art and what information is needed to meet future requirements. They uncover gaps in the state of the art and indicate areas where more research is needed. For example, figure R63-919 shows some preliminary design layouts from a study of possible planetary spacecraft propulsion systems. As you can observe, the configurations are combinations of engines using solids, storable liquid, and cryogenic liquid propellants. Other studies consider the potential applications of hybrid rockets and liquid rocket engines with air augmentation. Often these studies and preliminary designs lead the way to new approaches and significant gains in propulsion technology. Aerothermochemistry is a composite of thermodynamics, gas dynamics, and chemistry that considers the processes of propellant injection mixing and vaporization; ignition and combustion; and expansion of the combustion gases through the nozzle. Consider solid rocket combustion for example. Research on various aspects of solid combustion is underway at three universities (Princeton, Purdue, and Minnesota) and at three NASA centers (JPL, Lewis, and Langley). Last year we reported on work in low-pressure combustion where there were regions of stable and unstable burning. Since that time, an analytical method has been developed that correlates all the experimental data. The correlation predicts low pressure burning characteristics and hence, will be a valuable tool to engine designers. These results will be presented at the annual interagency meeting on solid propulsion at Seattle, Wash., this summer. The correlation will be extended to include propellants with metal additives. Other research includes ignition, the effect of rapid pressure decay on quenching combustion, on reignition, and basic combustion phenomena. A combustion problem of great concern to us is combustion oscillations. These are pressure fluctuations in the combustion chamber which greatly increase heat transfer, and can destroy the combustion chamber by excessive heating, pressure, or vibrations if allowed to continue. This is probably the greatest single problem in liquid rocket engine development and we need to increase our efforts in both basic studies of these complex phenomena and in engineering studies to devise techniques for controlling or eliminating these oscillations. Research is underway at Princeton University, the Lewis Research Center, and the Naval Ordnance Test Station on this problem. Recent results by the Lewis Research Center map out combustion stability regions as functions of vaporization characteristics of the fuels, their burning rate and engine size. In the coming year the work will be extended to larger engines and engineering solutions will be sought. One approach we expect to investigate more fully is the use of chemical additives to influence burning rate and avoid combustion oscillations. Dr. Kurzweg has described to you the basic research program on materials. We seek to apply this, plus related engineering knowledge of materials, to rocket engine applications. Work is underway at Armour Research Foundation to find high temperature coatings that resist the oxidizing atmospheres for use in rocket nozzles. Tungsten, for example, can withstand very high temperatures but oxidizes rapidly. When coated with a hafnia composite later, however, tungsten withstood oxidization successfully in a series of recent tests. Work at Marquardt and JPL seeks to apply pyrolytic graphite to small thrust engines. This technique allows the chamber to operate at very high temperatures and radiate its heat to the surrounding space. Propellants Unlike The subject of rocket propellants is complex and often controversial. air-breathing engines where the oxidizer is always the same and the fuels have remained within the hydrocarbon family, rocket propellants come in many chemical varieties. Almost every chemical reaction that releases a large amount of energy has been scrutinized. Often, as the technology advances or requirements change, chemicals that once were examined and passed over may become attractive. In this changing situation, it is well to keep in mind a few basic guides. From an energy standpoint, we seek chemical reactions that result in high gas temperatures and low weight of combustion products. This temperature, divided by average molecular weight of the gases, determines the specific impulse, or the amount of thrust produced per pound per second flow of propellants. From energy considerations, we generally confine ourselves to the first part of the periodic table with chemicals containing hydrogen, carbon, nitrogen, beryllium, boron, aluminum, oxygen, fluorine, and chlorine. If energy 96-504 0-63-pt. 3b-15 |